President Trump and North Korean leader Kim Jong Un signed a joint document after their summit in Singapore. Trump promised that denuclearization would come "very, very quickly."

RACHEL MARTIN, HOST:

And I'm Rachel Martin in Singapore, where we have watched history unfold.

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PRESIDENT DONALD TRUMP: Chairman Kim and I just signed a joint statement in which he reaffirmed his unwavering commitment to complete denuclearization of the Korean Peninsula.

DAVID GREENE, HOST:

That was President Trump in Singapore, sitting next to North Korea's leader, Kim Jong Un, after the two leaders signed an agreement aimed at ridding North Korea of its nuclear capabilities. And Rachel, you're there in Singapore watching all of this unfold, as you said. I mean, so many questions to answer now going forward about the substance of what exactly these two leaders agreed to - but it is something significant, just the fact that they got together, right?

MARTIN: The fact that this is even happening is huge. And there have been so many striking visual images over the past 24 hours. One that sticks with me, David, is the flags that were flying outside of the hotel where the summit actually happened - the American flag and the flag of North Korea flying side by side. We have got a team of reporters with us here in Singapore to help us decipher what has transpired, what's the significance of those flags flying next to each other and what the next steps in all this are going to be. Scott Horsley is our White House correspondent. He's had a front-row seat to everything today. Our Seoul-based correspondent Elise Hu is sitting next to me here at our makeshift studio in Singapore. And we've also got NPR's national security correspondent Greg Myre with us from D.C.

Hello to all three of you.

GREG MYRE, BYLINE: Hello, Rachel.

ELISE HU, BYLINE: Hello.

SCOTT HORSLEY, BYLINE: Good morning.

MARTIN: Scott, I'm going to start with you because you happen to be one of the very few reporters designated to follow President Trump throughout all the events today. Walk us through the choreography of what we saw.

HORSLEY: Well, choreography is the right word because this was a carefully staged summit meeting from the walk this morning down the red carpet to the Kodak moment - a handshake - the formal luncheon of sweet-and-sour crispy pork and then that signing ceremony that you just described at a elegant wooden table with the two leaders sitting side by side, signing what the president called a pretty comprehensive statement, but which is, in fact, only about a page and a quarter in length and which leaves a whole lot of details to be filled in later.

MARTIN: All right. So let's talk about what's in there and what's not. Start with what is actually in there, Scott.

HORSLEY: Well, as you say, the Korean leader, Kim Jong Un, has pledged to work towards the denuclearization of the Korean Peninsula. That's something he has promised to do in the past. There is nothing in this statement about a timetable or verification procedures or any real details of what denuclearization even means. In exchange, the United States offers security guarantees for the North Korean country and regime, and something that's not actually in the agreement, which President Trump talked about in a news conference that just wrapped up. The U.S. has agreed to suspend military exercises with South Korea, which have long been an irritant for the North Koreans. But remember, when this summit was first announced, one of the concessions that North Korea had supposedly made was they were going to stop complaining about those military exercises. Now you have the U.S. saying, you know, we're not going to do them anymore; if it bothers North Korea, we're going to cut it out. And the president himself said he thought it was a provocative move for the U.S. to have.

MARTIN: Elise Hu is our Seoul correspondent. Elise, you've been covering this story for more than three years. From your South Korean vantage point, what struck you about today? What do you see the significance of this being?

HU: Well, the fact that it happened at all is rather significant in and of itself because of where we were - I mean, we're talking just last year, a summer of...

MARTIN: Fire and fury.

HU: ...Fire and fury, a lot of hostile rhetoric. Last summer, I was preparing to travel to Guam, you know, where North Korea was considering a plan to bracket the U.S. territory with missiles. And so now we've seen a dramatic few months of rapprochement and Kim Jong Un's real shift to this statesmanlike role. He's now met with the Chinese leader, Xi Jinping, twice. He's met with Moon Jae-in - South Korea - twice. He's met Trump now in person and welcomed Sergey Lavrov of Russia to Pyongyang. So this is just whiplash, really, for a lot of us who've been covering this for the past year or so.

MARTIN: Right, and covering someone who rarely speaks. I mean, part of what the significance - there are so many symbolically significant moments of the past 24 hours, but to just hear the North Korean leader talking to reporters is monumental in and of itself. I think we've got a clip of him. Let's listen.

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SUPREME LEADER KIM JONG UN: (Through interpreter) Today, we had a historic meeting and decided to leave the past behind, and we are about to sign a historic document. The world will see a major change.

HU: Now, this world-will-see-a-major-change line - it has yet to bear fruit, of course. We are not able to judge this in the short term. But for a lot of Koreans and Korean-Americans, Korean people who are watching this, this goes way beyond the security question, way beyond the denuclearization-definition conversation that we have, right? It's really about the Korean identity that's been split by war and strife. And there's real hope, a cautious optimism among South Koreans and people of Korean descent that, you know, peace and some sort of engagement that leads to peace can be lasting.

MARTIN: Just having this opening - while there's still a lot to be determined, just having the opening could portend something peaceful in the long term. We've got Greg Myre in the studio, I think. Greg, you cover national security. You've been thinking about this story from that vantage point, from that perspective. There are a lot of holes in this agreement. What did you not hear or see that's significant?

MYRE: Well, any details about how North Korea might denuclearize. In fact, the statement talks about Kim - he says he reaffirmed his commitment to denuclearize. So in a sense, he's just repeating what he said previously. And President Trump got up and, in his fairly lengthy news conference, said, it's going to take a long time. Even just the mechanics of it, even if everybody agrees on a process, that will take a long time. So that's the kind of things we're looking for. We've been down this road before, and North Korea cheated, and it all fell apart. So we don't have the details. So much needs to be filled in.

MARTIN: You talk about...

HORSLEY: President Trump was actually pushed on that point. You know, how does he know that North Korea won't simply cheat, as they've done so often in the past? And his only real explanation is, well, I'm different; you know, there's a new president in town. So he seems convinced that his persona will drive new tactics from the North Koreans that we haven't seen in previous administrations.

MARTIN: But that's a valid point, right, Elise? These are two different individuals. Even though of the mechanisms for change are the same - whether or not to relieve economic sanctions, whether or not to decrease the U.S. military footprint on the Korean Peninsula - these two individual men come at this with different baggage, with different ideas about how to push it forward.

HU: Nothing is divorced from the context that it's in, and obviously, this context is very different. But the critics are going to really dig in on the point that, you know, each point - there's a four-point agreement - or four points in this agreement now, and each point has been previously agreed to in the - at least six or up to eight agreements that North Korea has signed onto regarding its nuclear program over the past couple of decades. So North Korea has signed onto these points before in different deals under different administrations, but in the past, they were more specific, and they were more comprehensive, in fact.

MARTIN: Greg, what tactically happens next? I mean, it's one thing to have the pomp and circumstance of this summit, which, as we have noted time and again, is significant in that it happened, but how do they start to fill in the contours of that agreement with concrete steps?

MYRE: The thing to look for will be lots of very detailed meetings between a bunch of wonkish technical people sitting down and going over very specific things and figuring out how this denuclearization process could work. Again, it would be North Korea suspending tests, which it's done - but extending the suspension of tests. And if you're really starting to move forward, North Korea has an estimated 20 to as many as 60 or 70 nuclear weapons. If you got to the point where you could see nuclear weapons being dismantled and shipped out, that would be real progress. But we're still a long way. They need to set up some committees and hold regular meetings to get the process moving.

MARTIN: Lastly, Scott Horsley - the president calling this a historic day - this is something that he has prioritized from the beginning of his administration, hasn't he?

HORSLEY: Yeah. I don't think there was ever a question that whatever came out of this meeting, the president was going to label it historic. And we're just going to have to wait and see now. He has sold the sizzle. Is there real beef here? Will there be real meat to this deal, and will there be verification of the commitments that Kim has now made?

MARTIN: All right. NPR White House correspondent Scott Horsley. We were also joined here in Singapore by NPR's Elise Hu, as well as national security correspondent Greg Myre - joined us on the line from Washington, D.C. Thanks to all of you guys.

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